Gas lift valve

ABSTRACT

A method for performing downhole gas lift operations includes coupling a gas lift valve to a tubing, wherein the gas lift valve includes an actuator, a flow control device disposed in the actuator, and a closure member that is initially in an open position; injecting a gas downhole and exterior to the tubing; urging the gas to enter the tubing via the gas lift valve; and creating a sufficient pressure differential across the gas lift valve to move the actuator, thereby causing the closure member to close the gas lift valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application Ser.No. 62/001,448 filed on May 21, 2014 and U.S. Provisional ApplicationSer. No. 61/881,663 filed on Sep. 24, 2013. Each of the aforementionedpatent applications is herein incorporated by reference.

BACKGROUND

1. Field

Embodiments of the present disclosure generally relate to valves capableof withstanding high injection pressures, high injection rates, orvarying injection pressure, including valves for use in hydrocarbonwells configured for artificial lift operations, for example.

2. Description of the Related Art

To obtain hydrocarbon fluids from an earth formation, a wellbore isdrilled into the earth to intersect an area of interest within aformation. The wellbore may then be “completed” by inserting casingwithin the wellbore and setting the casing therein using cement, forexample. In the alternative, the wellbore may remain uncased (an “openhole” wellbore), or may be only partially cased. Regardless of the formof the wellbore, production tubing is typically run into the wellboreprimarily to convey production fluid (e.g., hydrocarbon fluid, as wellas water and other, non-hydrocarbon gases) from the area of interestwithin the wellbore to the surface of the wellbore.

Often, pressure within the wellbore is insufficient to cause theproduction fluid to rise naturally through the production tubing to thesurface of the wellbore. Thus, to force the production fluid from thearea of interest within the wellbore to the surface, artificial liftmeans are sometimes employed. Gas lift and sucker rod pumping areexamples of artificial lift means for increasing production of oil andgas from a wellbore.

Gas lift systems are often the preferred artificial lifting systemsbecause operation of gas lift systems involves fewer moving parts thanoperation of other types of artificial lift systems, such as sucker rodlift systems. Moreover, because no sucker rod is required to operate thegas lift system, gas lift systems are usable in offshore wells havingsubsurface safety valves that would rule out the use of sucker rodpumping.

Gas lift systems commonly incorporate one or more valves in side pocketmandrels of the production tubing to enable the lifting of productionfluid to the surface. In a typical application, the gas lift valvesallow gas from the annulus between the casing and production tubing toenter the tubing through the valves, but prevent reverse flow ofproduction fluid from the tubing to the annulus.

SUMMARY

Embodiments of the present disclosure generally relate to a valveapparatus configured to close in response to a predetermined pressuredifferential across the valve apparatus. In one embodiment, the valveapparatus may be used in a gas lift operation. In use, the valveapparatus is initially in an open position, whereby fluid flow throughthe valve apparatus is allowed. The valve apparatus closes when apredetermined pressure differential is obtained across the valve.

In one embodiment, a method for performing downhole gas lift operationsincludes coupling a gas lift valve to a tubing, wherein the gas liftvalve includes an actuator, a flow control member disposed in theactuator, and a closure member that is initially in an open position;injecting a gas downhole and exterior to the tubing; urging the gas toenter the tubing via the gas lift valve; and creating a sufficientpressure differential across the gas lift valve to move the actuator,thereby causing the closure member to close the gas lift valve.

In another embodiment, a valve for controlling fluid flow between aninlet and an outlet includes a housing having a bore in fluidcommunication with an inflow port and an outlet port; a closure memberconfigured to close fluid communication through the bore; and a flowtube movable between an extended position and a retracted position,wherein when in the extended position, the flow tube retains the closuremember in an open position, and wherein the flow tube is movable to theretracted position in response to a predetermined pressure differentialacross the bore.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe various aspects, briefly summarized above, may be had by referenceto embodiments, some of which are illustrated in the appended drawings.It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a cross-sectional view of a gas injection wellbore, inaccordance with an embodiment of the present disclosure.

FIG. 2 illustrates an exemplary embodiment of a gas lift valve. FIG. 2Aillustrates an exemplary partial, cross-sectional view of the gas liftvalve.

FIGS. 3A-3G are sequential views of an exemplary embodiment of a gaslift operation.

FIG. 4 illustrates another exemplary embodiment of a gas lift valve.

FIG. 4A illustrates an exemplary partial, cross-sectional view of thegas lift valve.

FIGS. 5 and 6 illustrate an exemplary embodiment of a side pocketmandrel. FIG. 5 depicts an exemplary gas lift valve disposed in the sidepocket mandrel, and FIG. 6 depicts the gas lift valve disposed out ofthe side pocket mandrel.

FIG. 7A illustrates another exemplary embodiment of a gas lift valve inan open position.

FIG. 7B illustrates the gas lift valve of FIG. 7A in a closed position.

FIG. 7C illustrates an exemplary partial, cross-sectional view of thegas lift valve of FIG. 7A.

FIG. 7D illustrates an exemplary partial, cross-sectional view of thegas lift valve of FIG. 7A.

FIG. 7E illustrates an exemplary embodiment of a viscous type dampenerfor a gas lift valve.

FIG. 7F illustrates another exemplary embodiment of a friction typedampener for a gas lift valve.

FIG. 7G illustrates an exemplary embodiment of a detent device for a gaslift valve.

FIG. 8A illustrates another exemplary embodiment of a gas lift valve inan open position.

FIG. 8B illustrates the gas lift valve of FIG. 8A in a position before adetent is released.

FIG. 8C illustrates the gas lift valve of FIG. 8A in a closed position.

FIG. 9A illustrates another exemplary embodiment of a gas lift valve inan open position.

FIG. 9B illustrates the gas lift valve of FIG. 9A in a closed position.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide a valve apparatus capableof withstanding high injection pressures, high injection rates orvarying injection line pressure, and techniques for using the valveapparatus in various suitable applications. In one embodiment, a gaslift valve apparatus is configured to close in response to apredetermined pressure differential across the gas lift valve apparatus.

FIG. 1 illustrates a typical gas lift completion for hydrocarbonrecovery, which may include a wellhead 112 atop a casing 114 that passesthrough a formation 102. Production tubing 120 positioned in the casing114 may have a number of side pocket mandrels 130 and a productionpacker 122. To conduct a gas lift operation, operators may install gaslift valves 140 in the side pocket mandrels 130.

With the valves 140 installed, compressed gas G from the wellhead 112may be injected into the annulus 116 between the production tubing 120and the casing 114. In the side pocket mandrels 130, the gas lift valves140 are in the open position to allow injected gas and other fluids toflow from the annulus 116 into the tubing 120. When the velocity of thegas flowing through the valve 140 is above a predetermined value, thevalve 140 closes to prevent further inflow of the injected gas into thetubing 120.

Alternatively, a gas lift operation may be performed to gas lift fluidin the annulus 116. Compressed gas may be injected into the productiontubing 120. The gas lift valves 140 are in the open position to allowinjected gas and other fluids to flow from the tubing 120 into theannulus 116. When the velocity of the gas flowing through the valve 140is above a predetermined value, the valve 140 closes to prevent furtherinflow of the injected gas into the annulus 116.

Downhole, the production packer 122 forces upwards travel through theproduction tubing 120 of production fluid P entering casing perforations115 from the formation 102. Additionally, the packer 122 keeps the gasflow in the annulus 116 from entering the tubing 120.

The injected gas G passes down the annulus 116 until it reaches the sidepocket mandrels 130. Entering the mandrel's inlet ports 135, the gas Gfirst passes through the gas lift valve 140 before it can pass into theproduction tubing 120. Once in the tubing 120, the gas G can then riseto the surface, lifting production fluid P in the production tubing inthe process.

FIG. 2 illustrates an exemplary embodiment of a gas lift valve 200. FIG.2A is an enlarged, partial cross-sectional view of the gas lift valve200. The valve 200 may be positioned in a side pocket mandrel 130 of thegas lift completion system shown in FIG. 1. The valve 200 includes avalve housing 210 having one or more gas inlet ports 211 and one or moregas outlet ports 212. As shown, the inlet ports 211 are disposed at anupper portion of the valve 200 and the outlet ports 212 are disposed ata lower portion of the valve 200. A latch 216 is shown disposed at theupper end of the valve 200. A sealing member 215 such as a packing stackarrangement may be disposed on each side of the inlet ports 211 toisolate the fluid in the annulus 116 from the tubing 120. The inletports 211 and outlet ports 212 communicate via a bore 220 in the valve200. A closure member 230 is configured to selectively open or closefluid communication through the bore 220. Exemplary closure membersinclude a flapper, a ball and seat, a sealing head, and other suitableclosure members known to a person of ordinary skill in the art. In thisembodiment, a flapper 230 is positioned at an upper portion of the bore220. As shown, the flapper 230 is retained in an open position using anactuator such as a flow tube 240. The flow tube 240 is shown biased inan extended position using a biasing member 245 such as a spring. Thebiasing member 245 is disposed in an annular area 247 between the flowtube 240 and the valve housing 210. The biasing member 245 may engage anoptional spacer member 246 coupled to the flow tube 240.

A flow control member 250 is coupled to the interior of the flow tube240. In the embodiment shown in FIG. 2A, the flow control member 250 isan annular ring having an opening 255 therethrough. Although the flowtube 240 is shown as formed using two connected tubulars to facilitatecoupling with the flow control member 250, it is contemplated that theflow tube 240 may be formed using a single tubular, or three or moreconnected tubulars. The flow control member 250 forms an effective areain the bore 220 of the flow tube 240. The effective area may becontrolled by selecting the appropriate size of the inner diameter ofthe opening 255 of the flow control member 250. In this respect,injected fluid flowing in from the inlet ports 211 applies a force tothe flow control member 250, which force is opposed by the biasing forceof the spring 245. When the force applied by the injected flow is higherthan the biasing force, the flow tube 240 will compress the spring 245.As a result, the flow tube 240 is moved away from the flapper 230,thereby allowing the flapper 230 to close the bore 220. The closingpressure of the flapper 230 can be selected by adjusting the biasingforce of the spring 245, the inner diameter of the flow control member250, and combinations thereof. For example, a smaller diameter opening255 will close the flapper 230 using a smaller pressure differentialthan a larger diameter opening 255 when other parameters, such as theflow rate of injected fluid, the biasing force of the spring member 245,and the inner diameter of the bore 220, are fixed. During operation,when the biasing force of the spring member 245, the diameter of theopening 255 and the inner diameter of the bore 220 are fixed, anincrease in the flow rate of the injected gas will cause an increase indifferential pressure across the flow control member 250, and eventuallyclose the valve 200. After closing, fluid from the annulus 116 isprevented from entering the tubing 120. The flapper 230 can re-open whenthe casing pressure, tubing pressure, and spring force acting on theflapper dictates. In another embodiment, the valve 200 may include anoptional bleed port, which may also affect the re-opening of the flapper230.

In one embodiment, valve 200 may include an optional detent mechanism253 to retain the flow tube 240 in the retracted position. For example,at a predetermined pressure differential, the flow tube 240 is retractedsufficiently such that the detent mechanism 253 is activated, therebyretaining the flow tube 240 in the retracted position. An exemplarydetent mechanism 253 is a retractable pin configured to engage a recess254 in the flow tube 240. Another exemplary detent mechanism is acollet. In yet another embodiment, a one-way valve 257 such as a checkvalve may be disposed at the lower end of the valve 200. The one-wayvalve 257 may prevent fluid in the tubing 120 from entering the annulus116 via the valve 200.

FIGS. 3A-3G illustrate an exemplary sequence during a gas lift operationusing one embodiment of a gas lift completion system to unload a well301. Referring to FIG. 3 a, the gas lift completion system includes awellhead 312 disposed atop a casing 314 and a production tubing 320positioned in the casing 314. The production tubing 320 may have aplurality of gas lift valves 340 coupled to a respective side pocketmandrel and a production packer 322 at a lower end of the tubing 320.

As shown, the system 300 includes six velocity valves 340 a-340 f and anorifice valve 365 coupled to the tubing 320. In FIG. 3A, the well 301 isloaded with completion fluid, and the gas lift valves 340 a-340 f are inthe open position because no pressure differential exists across thevalves 340 a-340 f.

In FIG. 3B, injection gas 308 is supplied to assist with unloading ofthe well 301. Because the gas lift valves 340 a-340 f are open, thefluid in the annulus 316 is allowed to enter the tubing 320. As morepressure is applied to the casing 314, the fluid level 309 in theannulus 316 will drop. As shown, the fluid level 309 is above the firstvalve 340 a, and the injection gas 308 has not entered the first valve340 a. It must be noted that if the gas lift valves 340 a-340 f areclosed, the annulus fluid may enter the tubing 320 through the orificevalve 365.

In FIG. 3C, the fluid level 309 in the casing 314 has dropped to thedepth of the first gas lift valve 340 a, and the injected gas 308 hasbegun to enter the first gas lift valve 340 a and the tubing 320. Inthis respect, the injected gas 308 in the tubing 320 will aerate thefluid column in the tubing 320. The fluid in the casing 314 continues toenter through the orifice valve 365 and/or any of the gas lift valves340 b-340 f disposed below the first valve 340 a that are open.

In FIG. 3D, gas injection pressure has increased. The injected gas 308continues to flow in through the first valve 340 a, thereby continuingto aerate the fluid column in the tubing 320. Also, the fluid in thecasing 314 continues to enter the tubing 320 through the orifice valve365 and/or any of the gas lift valves 340 b-340 f below the first valve340 a that are open.

In FIG. 3E, the fluid level 309 has dropped to the depth of the secondgas lift valve 340 b, and the injected gas 308 has begun to enter thesecond gas lift valve 340 b. The first valve 340 a has closed due thepressure differential across the first valve 340 a. For example, theupstream pressure (e.g., the pressure at the inlet ports 211) may be at7,000 psi while the downstream pressure (e.g., the pressure at theoutlet ports 212) may be at 4,500 psi. The pressure differential of2,500 psi is sufficient to overcome the biasing force of the spring 245,thereby retracting the flow tube 240 and allowing the flapper 230, balland seat mechanism, a sealing head, or other suitable closure member toclose.

In FIG. 3F, gas injection pressure is increased. The injected gas 308continues to flow in through the second valve 340 b, thereby continuingto aerate the fluid column in the tubing 320. Also the fluid in thecasing 314 continues to enter the tubing 320 through the orifice valve365 and/or any of the gas lift valves 340 c-340 f below the second valve340 b that are open.

This process of creating a pressure differential to sequentially closean upper valve and causing the fluid level to drop so that injected gasmay flow through the next, lower valve continues until injected gasreaches an optimal point of injection. The optimal point of injection isa depth in the well where the gas injection point remains stationaryuntil the well condition makes it possible to inject gas deeper. All ofthe gas lift valves 340 a-340 f that are above the optimal point ofinjection have closed due to the pressure differential across thevalves.

FIG. 4 illustrates an exemplary embodiment of a gas lift valve 400. FIG.4A is an enlarged, partial cross-sectional view of the gas lift valve400. The valve 400 may be positioned in a side pocket mandrel 130 of thegas lift completion system shown in FIG. 1. It must be noted thatembodiments of the gas lift valves disclosed herein may be used withother suitable types of gas lift mandrels known to a person of ordinaryskill in the art. In the embodiment shown in FIG. 1, the valve 400 issimilar to the valve 200 of FIG. 2 in that the valve 400 includes manyof the components of the former valve 200. One difference between thevalves 200, 400 is the axial positions of the components of this valve400 have been inverted with respect to the latch 416. The valve 400includes a valve housing 410 having one or more gas inlet ports 411 andone or more gas outlet ports 412. As shown, the inlet ports 411 aredisposed at a lower portion of the valve 400 and the outlet ports 412are disposed at an upper portion of the valve 400. A latch 416 is showndisposed at the upper end of the valve 400. In this embodiment, theoutlet ports 412 are formed through the latch 416. A sealing member 415such as a packing stack arrangement may be disposed on each side of theinlet ports 411 to isolate the fluid in the annulus 116 from the tubing120. The inlet ports 411 and outlet ports 412 communicate via a bore 420in the valve 400. A closure member 430 is configured to selectively openor close fluid communication through the bore 420. Exemplary closuremembers include a flapper, a ball and seat, a sealing head, and othersuitable closure members known to a person of ordinary skill in the art.In this embodiment, a flapper 430 is positioned at a lower portion ofthe bore 420. The flapper 430 is retained in an open position using aflow tube 440. The flow tube 440 is shown biased in an extended positionusing a biasing member 445 such as a spring. The biasing member 445 isdisposed in an annular area 447 between the flow tube 440 and the valvehousing 410. The biasing member 445 may engage an optional spacer member446 coupled to the flow tube 440.

A flow control member 450 is coupled to the interior of the flow tube440. In the embodiment shown in FIG. 4A, the flow control member 450 isan annular ring having an opening 455 therethrough. Although the flowtube 440 is shown as formed using two connected tubulars to facilitatecoupling with the flow control member 450, it is contemplated that theflow tube 440 may be formed using a single tubular, or three or moreconnected tubulars. The flow control member 450 forms an effective areain the bore 420 of the flow tube 440. The effective area of the flowcontrol member 450 is determined by the difference in area between theinner diameter of the bore 420 and the inner diameter of the opening 455of the flow control member 450. In this respect, injected fluid flowingin from the inlet ports 411 applies a force to the flow control member450, which force is opposed by the biasing force of the spring 445. Whenthe force applied by the injected flow is higher than the biasing force,the flow tube 440 will compress the spring 445. As a result, the flowtube 440 is moved away from the flapper 430, thereby allowing theflapper 430 to close the bore 420. The closing pressure of the flapper430 can be selected by adjusting the biasing force of the spring 445,the effective area of the flow control member 450, and combinationsthereof. After closing, fluid from the annulus 116 is prevented fromentering the tubing 120. The closing pressure of the flapper 430 can beselected by adjusting the biasing force of the spring 445, the innerdiameter of the flow control member 450, and combinations thereof. Forexample, a smaller diameter opening 455 will close the flapper 430 usinga smaller pressure differential than a larger diameter opening 455 whenother parameters, such as the flow rate of injected fluid, the biasingforce of the spring member 445, and the inner diameter of the bore 420,are fixed. During operation, when the biasing force of the spring member445, the diameter of the opening 455 and the inner diameter of the bore420 are fixed, an increase in the flow rate of the injected gas willcause an increase in differential pressure across the flow controlmember 450, and eventually close the valve 400. After closing, fluidfrom the annulus 116 is prevented from entering the tubing 120. Theflapper 430 can re-open when the casing pressure, tubing pressure, andspring force acting on the flapper dictates. In another embodiment, thevalve 400 may include an optional bleed port, which may also affect there-opening of the flapper 430. Although the embodiment is describedusing a flapper 430, it must be noted that a ball and seat, a sealinghead, or other suitable types of closure members are contemplated.

In one embodiment, the valve 400 may include an optional detentmechanism 453 to retain the flow tube 440 in the retracted position. Forexample, at a predetermined pressure differential, the flow tube 440 isretracted sufficiently such that the detent mechanism 453 is activated,thereby retaining the flow tube 440 in the retracted position. Anexemplary detent mechanism 453 is a retractable pin configured to engagea recess 454 in the flow tube 440. Another exemplary detent mechanism isa collet. In yet another embodiment, a one-way valve 457 such as a checkvalve may be disposed at the lower end of the valve 400. The one-wayvalve 457 may prevent fluid in the tubing 120 from entering the annulus116 via the valve 400.

FIGS. 5 and 6 illustrate an exemplary side pocket mandrel suitable forreceiving a gas lift valve according to embodiments of the presentinvention. FIG. 5 depicts a valve 500 disposed in the side pocketmandrel 530, and FIG. 6 depicts the valve 500 disposed out of the sidepocket mandrel 530. Referring to FIG. 6, the side pocket mandrel 530 mayinclude external check valves disposed at the entrance of the passageinto the pocket 532 of the side pocket mandrel 530. Although twopassages are shown, it is contemplated that the side pocket mandrel 530may include a single passage or three or more passages. The pocket 532is configured to receive the valve 500 and is in fluid communicationwith the tubing 120. When the valve 530 is not installed, fluid from thetubing 120 may enter the pocket 532, but is prevented from exitingthrough the passages by the respective check valves. When the valve 500is in the pocket 530 as shown in FIG. 5, the pressure of the injectiongas may overcome the check valves, thereby allowing the injection gas toenter the passages and flow toward the gas lift valve 500. Afterentering the inlet ports of the gas lift valve 500, the injection gasmay exit through the outlet ports, flow through the pocket 532, and flowinto the tubing 120, where the injection gas may aerate the fluid columnin the tubing 120. The injection gas may continue to enter and exit thegas lift valve 500 until the pressure differential across the gas liftvalve is sufficient to overcome the biasing force of the biasing member,thereby retracting the flow tube and allowing the flapper to close. Itis contemplated that other suitable types of gas lift mandrels known toa person of ordinary skill in the art may be used with embodiments ofthe gas lift valves disclosed herein.

In yet another embodiment, when the gas lift valves are used inconjunction with the orifice valve, such as a shear-orifice valve, acasing annulus test may be performed without wireline intervention. Inyet another embodiment, the gas lift valve may include a dampener deviceto facilitate movement between the open and close position. In yetanother embodiment, the flow control device of the gas lift valve mayinclude a venturi choke to improve gas passage through the gas liftvalve.

FIG. 7A illustrates an exemplary embodiment of a gas lift valve 700 inan open position. FIG. 7B illustrates the gas lift valve 700 in a closedposition. FIG. 7C illustrates an exemplary partial, cross-sectional viewof the gas lift valve 700. The gas lift valve 700 may be positioned in aside pocket mandrel 130 of the gas lift completion system shown in FIG.1.

The gas lift valve 700 includes a valve housing 710. The valve housing710 has a bore 720, one or more gas inlet ports 711 and one or more gasoutlet ports 712. As shown in FIG. 7A, the inlet ports 711 are disposedat a lower portion of the gas lift valve 700 and the outlet ports 712are disposed at an upper portion of the gas lift valve 700. The inletports 711 and outlet ports 712 communicate via the bore 720. A flow tube740 is disposed in the valve housing 710. A check valve 757 is disposedin the bore 720. The check valve 757 may prevent fluid in the tubing 120from entering the annulus 116 via the gas lift valve 700. A latch 716 isshown disposed at the upper end of the gas lift valve 700 to allow thegas lift valve 700 be positioned in a side pocket mandrel 130. A sealingmember 715, such as a packing stack arrangement, may be disposed on eachside of the inlet ports 711 to isolate the fluid in the annulus 116 fromthe tubing 160.

The flow tube 740 may be formed by a singular tubular or two or moreconnected tubular. The flow tube 740 has a sealing head 730 forming ablind end. The sealing head 730 may be formed unitarily on the flow tube740 or attached to the flow tube 740. One or more tube inlets 732 areformed through the flow tube 740 above the sealing head 730. The tubeinlets 732 provide fluid communication between the inlet ports 711 andthe outlet ports 712 through the bore 720. A seal member 734 is disposedinside the valve housing 710. In one embodiment, the sealing head 730includes an upper end 730U connected to the fluid tube 740 and lower end730L extending below the upper end 730U. The sealing head 730 mayinclude a conical portion so that the outer diameter of the upper end730U is smaller than the outer diameter of the end 730L. The conicalportion forms having an inclined surface 730S matching the seal member734. The sealing head 730 moves relative to the seal member 734 toselectively open or close fluid communication through the bore 720.

The flow tube 740 includes a flow control member 750 coupled to theinterior of the flow tube 740. In the embodiment shown in FIG. 7C, theflow control member 750 is an annular ring having an opening 755therethrough. The flow control member 750 forms an effective area in theflow tube 740. The flow tube area may be controlled by selecting theappropriate size of the inner diameter of the opening 755 of the flowcontrol member 750.

A biasing member 745 is disposed in an annular area 747 between the flowtube 740 and the valve housing 710. The flow tube 740 is biased in anopen position, as shown in FIG. 7A, by the biasing member 745. Thebiasing member 745 may be a spring. An optional spacer member 746coupled to the flow tube 740 may engage the biasing member 745 to adjustthe position of the flow tube 740 and the bias force of the biasingmember 745. The spacer member 746 may be a lock nut.

When the gas lift valve 700 is in the open position as shown in FIG. 7A,injected fluid flows in from the inject ports 711, through the tubeinlets 732 to into the flow tube 740, then through the opening 755 ofthe flow control member 750 and the check valve 757 to the outlet ports712. The injected fluid flowing in from the inlet ports 711 applies aforce to the flow control member 750, which force is opposed by thebiasing force of the biasing member 745.

When the force applied by the injected fluid is higher than the biasingforce, the flow tube 740 will compress the biasing member 745. As aresult, the flow tube 740 moves and the sealing head 730 moves towardsthe seal member 734. When pressure differential across the flow controlmember 750 reaches a closing pressure differential, the sealing head 730moves to a closed position and contacts the seal member 734, as shown inFIG. 7B. In the closed position, a seal is formed between the sealinghead 730 and the seal member 734 to close the bore 720.

When the gas lift valve 700 is at the closed position, fluid from theannulus 116 is prevented from entering the tubing 120. The sealing head730 may move down to re-open the gas lift valve 700 when the casingpressure, tubing pressure, and spring force acting on the effective areaof the flow control member 750 in the flow tube 740 dictate.

The closing pressure differential of the gas lift valve 700 can beadjusted by selecting the biasing force of the spring member 745, theinner diameter of the flow control member 750, and the combinationsthereof. For example, a smaller diameter opening 755 will close thesealing head 730 using a smaller pressure differential than a largerdiameter opening 755 when other parameters, such as the flow rate ofinjected fluid and the biasing force of the spring member 745, arefixed. During operation, when the biasing force of the spring member 745and the diameter of the opening 755 are fixed, an increase in the flowrate of the injected fluid will cause an increase in differentialpressure across the flow control member 750, and eventually close thevalve 700.

The closing pressure differential of the gas lift valve 700 can also beadjusted by manipulating the travel distance 733 of the flow tube 740.FIG. 7D is a partial cross-sectional view of the gas lift valve 700illustrating the travel distance 733 of the flow tube 740 from the openposition to the closed position. The longer the travel distance 733, themore compressed the bias member 745 is at the closed position. When thetravel distance 733 is too long, the gas lift valve 700 may not close.When the travel distance 733 is too short, the gas lift valve 700 mayclose too quickly. Additionally, the relative position between the inletports 711 and the tube inlets 732 may affect the closing pressuredifferential. The relative positions of the tube inlets 732, the inletports 711, and the lower end 730L of the sealing head 730, and thebiasing force of the spring 745 may be pre-set so that the closingpressure differential across the flow control member 750 moves the lowerend 730 of the sealing head 730 above the inlet ports 711. Once thesealing head 730 is positioned above the inlet ports 711, the forceapplied to the large surface area of the lower end 730 by the injectedfluid pushes the sealing head 730 further to enable a snap close thevalve 700.

In one embodiment, the gas lift valve 700 may include an optionaldampener to dampen potential rapid oscillation of the flow tube 740.FIG. 7E illustrates an exemplary embodiment of a dampener 760 suitablefor use with the gas lift valve 700. The dampener 760 may be a viscoustype dampener disposed in the valve housing 710 under the sealing head730. The dampener 760 may include a cylinder 764 filled with a fluid ofhigh viscosity, such as oil. A piston 763 having a restricted flow pathis movably disposed in the cylinder 764. A shaft 762 extends from thepiston 763 out of the cylinder 764 to connect with the sealing head 730.The motion of the flow tube 740 urges the piston 763 to move up or downin the cylinder 764, thereby forcing the fluid in the cylinder 764 toflow through the restricted path in the piston 763. The fluid flowingthrough the restricted path dampens rapid oscillation of the flow tube740.

FIG. 7F illustrates another exemplary embodiment of a dampener 770 forthe gas lift valve 700. The dampener 770 may be a friction typedampener. The dampener 770 may include a piston 774 disposed in thevalve housing 710 below the sealing head 730. A shaft structure 772extends from the piston 774 is coupled to the sealing head 730. Themotion of the flow tube 740 urges the piston 774 to move up or down inthe valve housing 710, thereby generating friction (between the piston774 and the valve housing 710). The friction dampens oscillation of theflow tube 740.

In one embodiment, the gas lift valve 700 may include an optional detentmechanism 753 to retain the flow tube 740 in a fully open or a fullyclosed position. The detent mechanism 753 may include a housing 754 anda spring energized ball structure 758. The spring energized ballstructure 758 may be fixedly connected to the sealing head 730 by ashaft 756. When the flow tube 740 is at a fully open position or a fullyclosed position, the spring energized ball structure 758 is locked intogrooves in the housing 754 to keep the flow tube 740 at the fully openposition or the fully closed position. The detent mechanism 753 improvesflow characteristic through the gas lift valve 700. The detent mechanism753 may also prevent rapid oscillation of the flow tube 740.

FIG. 8A illustrates another exemplary embodiment of a gas lift valve 800in an open position. FIG. 8B illustrates the gas lift valve 800 in aposition before a detent is released. FIG. 8C illustrates the gas liftvalve 800 in a closed position. The gas lift valve 800 may be positionedin a side pocket mandrel 130 of the gas lift completion system shown inFIG. 1. The gas lift valve 800 includes many of the components of thegas lift valve 700. One difference between the valves 700, 800 is thegas lift valve 800 includes a detent mechanism that provides valveclosure not directly dependent on flow rate.

The gas lift valve 800 includes a valve housing 810. The valve housing810 has a bore 820, one or more gas inlet ports 811 and one or more gasoutlet ports 812. The inlet ports 811 are disposed at a lower portion ofthe gas lift valve 800 and the outlet ports 812 are disposed at an upperportion of the gas lift valve 800. The inlet ports 811 and outlet ports812 communicate via the bore 820. A flow tube 840 is disposed in thevalve housing 810. A check valve 857 is disposed in the bore 820. Thecheck valve 857 may prevent fluid in the tubing 120 from entering theannulus 116 via the gas lift valve 800. A sealing member 815, such as apacking stack arrangement, may be disposed on each side of the inletports 811 to isolate the fluid in the annulus 116 from the tubing 160.

The flow tube 840 includes a lower flow tube assembly 880 and an upperflow tube assembly 886. The lower flow tube assembly 880 overlaps withthe upper flow tube assembly 886 in the middle section where the lowerflow tube assembly 880 encases the upper flow tube assembly 886. Thelower flow tube assembly 880 and the upper flow tube assembly 886 maymove relative to each other changing the length of the overlappingsection. Each of the flow tube assemblies 880, 886 may be formed by asingular tubular or two or more connected tubular.

The lower flow tube assembly 880 has a sealing head 830 forming a blindend. The sealing head 830 may be formed unitarily on an end section ofthe lower flow tube assembly 880 or attached to the lower flow tubeassembly 880. One or more tube inlets 832 are formed through the lowerflow tube assembly 880 above the sealing head 830. The tube inlets 832provide fluid communication between the inlet ports 811 and the outletports 812 through the bore 820. A seal member 834 is disposed inside thevalve housing 810. The sealing head 830 has an inclined surface matchingthe seal member 834. The sealing head 830 moves relative to the sealmember 834 to selectively open or close fluid communication through thebore 820.

A flow control member 850 is coupled to the interior of the upper flowtube assembly 886. The flow control member 850 is an annular ring havingan opening 855 therethrough. The flow control member 850 forms arestricted area in the flow tube 840. The flow tube area may becontrolled by selecting the appropriate size of the inner diameter ofthe opening 855 of the flow control member 850. A biasing member 845 isdisposed around the upper flow tube assembly 886 in an annular area 847between the flow tube 840 and the valve housing 810. The biasing member845 may be a spring compressed to bias the sealing head 830 to an openposition, as shown in FIG. 8A. An optional spacer member 846 coupled tothe upper flow tube assembly 886 may engage the biasing member 845 toadjust the position of the sealing head 830 and the bias force of thebiasing member 845. The spacer member 846 may be a lock nut.

The gas lift valve 800 also includes a detent mechanism 853 to retainthe lower flow tube assembly 880 along with the sealing head 830 in afully open position. The detent mechanism 853 may include a retractablepin 884. The retractable pin 884 may extend through an opening in thelower flow tube assembly 880 to lock the lower flow tube assembly 880 atthe open position, as shown in FIG. 8A. The retractable pin 884 mayretract from the lower flow tube assembly 880 by a release mechanism885. In one embodiment, the release mechanism 885 may be a protrusion onthe upper flow tube assembly 886. A detent spring 882 is compressed atthe open position and biases the lower fluid tube assembly 880 towardsthe closed position. The detent spring 882 enables the gas lift valve800 to snap close when the detent mechanism 853 is released.

When the gas lift valve 800 is in the open position as shown in FIG. 8A,injected fluid flows in from the inject ports 811, through the tubeinlets 832, into the lower flow tube assembly 880 and the upper flowtube assembly 886, then through the opening 855 of the flow controlmember 845, through the check valve 857, and exits via the outlet ports812. The detent mechanism 853 locks the lower flow tube assembly 880with the sealing head 830 at the open position. The injected fluidflowing in from the inlet ports 811 applies a force to the flow controlmember 850, which force is opposed by the biasing force of the biasingmember 845.

When the flow rate increases, the pressure differential across the flowcontrol member 850 increases, thereby moving the upper flow tubeassembly 886 upwards and compressing the biasing member 845 while thelower flow tube assembly 880 remains locked by the detent mechanism 853and the gas lift valve 800 remains in the open position, as shown inFIG. 8B. The upper flow tube assembly 886 moves relative to the lowerflow tube assembly 880 until the pressure differential across the flowcontrol member 850 reaches a predetermined closing pressuredifferential, at which point the detent mechanism 853 releases the lowerflow tube assembly 880 and the detent spring 882 pushes the lower flowtube assembly 880 towards the closed position, as shown in FIG. 8C. Thedetent mechanism 853 provides fast valve closure and prevents the gaslift valve 800 from oscillation from fluctuation of flow rate throughthe gas lift valve 800. Once the pressure below the sealing head 830 isreduced or equalized, the biasing member 845 will push the upper flowtube assembly 886 and lower flow tube assembly 880 downward to re-openthe gas lift valve 800 and the detent mechanism 853 will automaticallyre-lock the gas lift valve 800 at the open position.

FIG. 9A illustrates an exemplary embodiment of a gas lift valve 900 inan open position. FIG. 9B illustrates the gas lift valve 900 in a closedposition. The gas lift valve 900 may be positioned in a side pocketmandrel 130 of the gas lift completion system shown in FIG. 1. The gaslift valve 900 is similar to the gas lift valve 700. The differencebetween the gas lift valve 900 and the gas lift valve 700 is that thatgas lift valve 900 includes a ball and seat closure member.

The gas lift valve 900 includes a valve housing 910. The valve housing910 has a bore 920, one or more gas inlet ports 911 and one or more gasoutlet ports 912. As shown in FIG. 9A, the inlet ports 911 are disposedat a lower portion of the gas lift valve 900 and the outlet ports 912are disposed at an upper portion of the gas lift valve 900. The inletports 911 and outlet ports 912 communicate via the bore 920. A flow tube940 is disposed in the valve housing 910. A check valve 957 is disposedin the bore 920. The check valve 957 may prevent fluid in the tubing 120from entering the annulus 116 via the gas lift valve 900. A latch 916 isshown disposed at the upper end of the gas lift valve 900 to allow thegas lift valve 900 be positioned in a side pocket mandrel 130.

940The flow tube 940 may be formed by a singular tubular or two or moreconnected tubular. A closure member 930 is disposed in the valve housing910. As shown in FIG. 9A, the closure member 930 may be a ball having acentral through hole 935 for selectively to allow fluid flow and anouter slot 933 to engage an actuator. The flow tube 940 may include oneor more pins 943 positioned to engage with the closure member 930. Theone or more pins 943 may insert into the outer slot 933 of the closuremember 930 so that vertical movement of the pins 943 rotates the closuremember 930 to selectively open or close fluid communication through thebore 920.

The flow tube 940 includes a flow control member 950 coupled to theinterior of the flow tube 940 of the flow tube 940. The flow controlmember 950 may be an annular ring having an opening 955 therethrough.The flow control member 950 forms a choke in the flow tube 940. Theeffective area of the choke may be controlled by selecting theappropriate size of the inner diameter of the opening 955 of the flowcontrol member 950.

A biasing member 945 is disposed in an annular area 947 between the flowtube 940 and the valve housing 910. The flow tube 940 is biased in anopen position, as shown in FIG. 9A, by the biasing member 945. Thebiasing member 945 may be a spring. An optional spacer member 946coupled to the flow tube 940 may engage the biasing member 945 to adjustthe position of the flow tube 940 and the bias force of the biasingmember 945. The spacer member 946 may be a lock nut.

When the gas lift valve 900 is in the open position shown in FIG. 9A,injected fluid flows in from the inject ports 911, through the centralthrough hole 935 of the closure member 930 into the flow tube 940, thenthrough the opening 955 of the flow control member 945 and the checkvalve 957 to the outlet ports 912. The injected fluid flowing in fromthe inlet ports 911 applies a force to the flow control member 950,which force is opposed by the biasing force of the biasing member 945.

When the force applied by the injected fluid is higher than the biasingforce, the flow tube 940 will compress the biasing member 945. As aresult, the flow tube 940 moves up causing the closure member 930 torotate. When pressure differential across the flow control member 950reaches a closing pressure differential, the closure member 930 rotatesto the closed position, as shown in FIG. 9B.

Embodiments of the present disclosure provide a valve apparatusconfigured to close when a predetermined pressure differential acrossthe valve apparatus is reached. Because the valve apparatus does notdepend on bellows, the valve apparatus may be used in high injectionpressure and/or high injection rate, and/or high injection volumeapplications and is suitable for most deepwater applications. Forexample, the valve apparatus is capable of withstanding extremely highpressures, e.g., from about 1,000 psi to about 10,000 psi, from about5,000 psi to about 10,000 psi, from about 7,000 psi to 10,000 psi, atleast 7,000 psi, or at least 10,000 psi. In another example, the valveapparatus is capable of withstanding injection rates from about 0.5 toabout 15 million cubic feet per day; preferably from about 7.5 to about15 million cubic feet per day.

One embodiment of the present disclosure provides a method forperforming downhole gas lift operations. The method includes coupling agas lift valve to a tubing, wherein the gas lift valve comprises anactuator, a flow control member disposed in the actuator, and a closuremember that is initially in an open position, injecting a gas downholeand exterior to the tubing, urging the gas to enter the tubing via thegas lift valve, and creating a sufficient pressure differential acrossthe gas lift valve to move the actuator, thereby causing the closuremember to close the gas lift valve.

In one or more of the embodiments described herein, the gas lift valvefurther includes a housing having an inlet and an outlet, andabiasingmember for biasing the actuator in an extended position, wherein theclosure member is configured to selectively close a bore through thehousing, the actuator is movable between the extended position and aretracted position, and the actuator, when in the extended position,retains the closure member in an open position.

In one or more of the embodiments described herein, the actuatorcomprises a flow tube, and the flow control member is coupled to aninterior of the flow tube.

In one or more of the embodiments described herein, the closure memberis a sealing head disposed at one end of the flow tube.

In one or more of the embodiments described herein, the closure memberis selected from a flapper, a sealing head on the actuator, and a balland seat.

In one or more of the embodiments described herein, a plurality of gaslift valves is coupled to the tubing and axially spaced apart along thetubing.

In one or more of the embodiments described herein, the method furthercomprises sequentially closing the plurality of gas lift valves.

In one or more of the embodiments described herein, the method furthercomprises flowing the gas through a first gas lift valve and flowing aliquid through a second gas lift valve.

In one or more of the embodiments described herein, the method includesurging a liquid to enter the tubing via an orifice valve in fluidcommunication with the tubing. In one embodiment, the orifice valve isdisposed below the gas lift valve.

In one or more of the embodiments described herein, a closing pressuredifferential is adjustable by adjusting a force of the biasing memberand/or a travel distance of the actuator between the extended positionand the open position.

In one or more of the embodiments described herein, the method includesincreasing the pressure differential by decreasing the pressuredownstream from the gas lift valve.

In one or more of the embodiments described herein, the actuatorcomprises a flow tube, and the flow control member is disposed in aninterior of the flow tube.

In one embodiment, a method for performing downhole gas lift operationsincludes coupling a gas lift valve to a tubing, wherein the gas liftvalve comprises an actuator, a flow control member disposed in theactuator, and a closure member that is initially in an open position,injecting a gas downhole and interior to the tubing, urging the gas toexit the tubing via the gas lift valve, and creating a sufficientpressure differential across the gas lift valve to move the actuator,thereby causing the closure member to close the gas lift valve.

In one embodiment, a valve for controlling fluid flow includes a housinghaving a bore in fluid communication with an inflow port and an outletport, a closure member configured to close fluid communication throughthe bore, a flow tube movable between an extended position and aretracted position, and a flow control device disposed in the flow tube,wherein when in the extended position, the flow tube retains the closuremember in an open position, and wherein the flow tube is movable to theretracted position in response to a predetermined pressure differentialacross the bore.

In one or more of the embodiments described herein, the valve furthercomprises a biasing member for biasing the flow tube in the extendedposition.

In one or more of the embodiments described herein, the flow controldevice provides an effective area for urging the flow tube toward theretracted position in response to the pressure differential.

In one or more of the embodiments described herein, the valve furthercomprises a detent mechanism for retaining the flow tube in theretracted position or the extended position.

In one or more of the embodiments described herein, the valve furthercomprises a latch member.

In one or more of the embodiments described herein, the outlet port isformed through the latch member.

In one or more of the embodiments described herein, the closure memberis selected from the group consisting of a flapper, a sealing head onthe flow tube, and a ball and seat.

In one or more of the embodiments described herein, the closure membercomprises a sealing head attached to the flow tube.

In one or more of the embodiments described herein, the valve furthercomprises a seal member disposed in the housing, wherein the sealinghead moves relative to the seal member to selectively open or closefluid communication through the valve.

In one or more of the embodiments described herein, the flow tubeincludes one of more tube inlets adjacent to the sealing head.

In one or more of the embodiments described herein, the valve furthercomprises a dampener attached to the sealing head.

In one or more of the embodiments described herein, the valve furthercomprises a check valve disposed adjacent the outlet port.

In one or more of the embodiments described herein, the valve furthercomprises a dampener coupled to the flow tube.

In one or more of the embodiments described herein, the flow controldevice is fixedly coupled to the flow tube.

In one or more of the embodiments described herein, the flow controldevice comprises an annular ring coupled to an interior of the flowtube.

In one or more of the embodiments described herein, a re-open pressureis determined by an inner diameter of the bore, an inner diameter of theflow control device, and a force of the biasing member.

In one or more of the embodiments described herein, the valve isconfigured to operate in an external pressure from about 1,000 psi andabout 10,000 psi.

In one or more of the embodiments described herein, the valve isconfigured to operate with an injection gas rate from about 0.5 to about15 million cubic feet per day.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method for performing downhole gas lift operations, comprising:coupling a gas lift valve to a tubing, wherein the gas lift valvecomprises an actuator, a flow control member disposed in the actuator,and a closure member that is initially in an open position; injecting agas downhole and exterior to the tubing; urging the gas to enter thetubing via the gas lift valve; and creating a sufficient pressuredifferential across the gas lift valve to move the actuator, therebycausing the closure member to close the gas lift valve.
 2. The method ofclaim 1, wherein the gas lift valve further includes: a housing havingan inlet and an outlet; and a biasing member for biasing the actuator inan extended position, wherein the closure member is configured toselectively close a bore through the housing, the actuator is movablebetween the extended position and a retracted position, and theactuator, when in the extended position, retains the closure member inan open position.
 3. The method of claim 1, wherein the closure memberis selected from a flapper, a sealing head on the actuator, and a balland seat.
 4. The method of claim 1, further comprising sequentiallyclosing a plurality of gas lift valves, wherein the plurality of gaslift valves is coupled to the tubing and axially spaced apart along thetubing.
 5. The method of claim 1, wherein a closing pressuredifferential is adjustable by adjusting a force of the biasing memberand/or a travel distance of the actuator between the extended positionand the open position.
 6. The method of claim 1, wherein the actuatorcomprises a flow tube, and the flow control member is disposed in aninterior of the flow tube.
 7. The method of claim 6, wherein the closuremember is a sealing head disposed at one end of the flow tube.
 8. Amethod for performing downhole gas lift operations, comprising: couplinga gas lift valve to a tubing, wherein the gas lift valve comprises anactuator, a flow control member disposed in the actuator, and a closuremember that is initially in an open position; injecting a gas downholeand interior to the tubing; urging the gas to exit the tubing via thegas lift valve; and creating a sufficient pressure differential acrossthe gas lift valve to move the actuator, thereby causing the closuremember to close the gas lift valve.
 9. A valve for controlling fluidflow, comprising: a housing having a bore in fluid communication with aninflow port and an outlet port; a closure member configured to closefluid communication through the bore; a flow tube movable between anextended position and a retracted position; and a flow control devicedisposed in the flow tube, wherein when in the extended position, theflow tube retains the closure member in an open position, and whereinthe flow tube is movable to the retracted position in response to apredetermined pressure differential across the bore.
 10. The valve ofclaim 9, wherein the closure member is selected from the groupconsisting of a flapper, a sealing head on the flow tube, and a ball andseat.
 11. The valve of claim 10, wherein the closure member comprises asealing head attached to the flow tube.
 12. The valve of claim 11,further comprising a seal member disposed in the housing, wherein thesealing head moves relative to the seal member to selectively open orclose fluid communication through the valve.
 13. The valve of claim 11,wherein the flow tube includes one of more tube inlets adjacent to thesealing head.
 14. The valve of claim 9, further comprising a dampenercoupled to the flow tube.
 15. The valve of claim 9, wherein the flowcontrol device is fixedly coupled to the flow tube.
 16. The valve ofclaim 9, further comprising a detent mechanism for retaining the flowtube in the retracted position or the extended position.
 17. The valveof claim 9, further comprising a biasing member for biasing the flowtube in the extended position.
 18. The valve of claim 17, wherein theflow control device provides an effective area for urging the flow tubetoward the retracted position in response to the pressure differential.19. The valve of claim 9, further comprising a latch member.
 20. Thevalve of claim 9, wherein the flow control device comprises an annularring coupled to an interior of the flow tube.